China published coordinates for the zone at the weekend. The area covers most of the East China Sea and the skies over a group of uninhabited islands at the centre of a bitter row between Beijing and Tokyo.

Civil aviation officials from Hong Kong and Taiwan said their carriers entering the zone must send flight plans to the Chinese aviation authorities.

Singapore Airlines and Qantas Airways said they would keep the Chinese authorities informed of their flights through the area.

Korean Air said its flight plans would be delivered to the Chinese authorities, but the routes would not be affected. Japan Airlines and ANA Holdings also said the zone had not affected their flights.

Japan and its close ally, the United States, sharply criticised Beijing's move, which experts said was aimed at chipping away at Tokyo's claim to administrative control over the area, including the islands known as Senkaku in Japan and Diaoyu in China.

While China said the new rules would not affect normal operations for international flights, it added that it would take "defensive emergency measures" against aircraft that failed to identify themselves properly.

China's latest move could help spread the view that Japan was losing administrative control of the area, said Mr Hiroko Maeda, research fellow at Japanese think- tank the PHP Institute.

"China has already been sending its ships (there)," Mr Maeda said, adding: "It is clear China is trying to undermine Japan's administrative control. Now, it is stepping up its effort in the sky as well."

The Straits Times

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